Warning!!! Tech Support will refuse warranty service for speaker problems if the VLC media player is installed on the laptop. This exclusion is NOT disclosed in the laptop warranty! Remove all players before contacting Tech Support, leaving only Windows Media Player.
I'm wondering if the convoluted process described in this thread is still required to install the D630 audio driver when installing Windows XP on a D630. I see that on Dec. 20 a new Sigmatel driver was released (see http://support.dell.com/support/downloads/download.aspx?c=us&cs=555&l=en&s=biz&releaseid=R171789&SystemID=LATITUDE%20D630&servicetag=&os=WW1&osl=en&deviceid=8907&devlib=0&typecnt=0&vercnt=2&catid=-1&impid=-1&formatcnt=1&libid=3&fileid=235761). Did it resolve the problem?
I was experiencing this exact problem
Yes this solution you posted works. Sound is working now.